Furnace for roasting sulphide and other ores



14, 1930 E. RAcQ 1,778,415

FURNACE FOR ROASTING SULPHIDE AND OTHER ORES Filed Feb. 11, 1926 2Sheets-$haet 1 Oct. 14, 1930. E. BRACQ FURNACE FOR ROASTING SULPHIDE ANDOTHER ORES Filed Feb. 11, 1926 2 h etsheet- 2 ,fnvenz'or MILE BKH c QPatented Oct. 14, 1930 UNITED STATES PATENT OFFICE EIILE BBACQ, PAS DEGALAIB, FRANCE 1'11 RNACE FOB BOASTING SULPHIDE OTHER om Applicationfled February 11, 1836, Serial No. 87,728, and in France larch 9, 1825.

This invention relates to improvements in helical hearth furnaces orfurnaces having superimposed hearths, for roasting sulphide and otherores.

O The arrangement is characterized by a central chamber of largedimensions. The hearths are thus easily accessible from within thefurnace. Moreover, the operations of carrying out the process with theaid of I. inner windows or inspection openings, cooling the scrapers bynaturalmeans and rapidly replacing damaged elements may be carried outfrom within the furnace. In this arrangement all the actuating mechanismis l supported on a central rotating platform and is disposed incirculated air facilitating its operation. Thus the scrapers only aresub- 'ected to the action of the inner heat of comustion of the oreswhereas all the other elements such as scraper holders and the like areprotected therefrom.

The essential features of the above-mentioned arrangement are asfollows:

1. A central column through which, if necessary, cooling air may be suplied in a practical way to the scrapers and t eir holders which areguided on the said column and are designed for the rapid mounting andtaking down of the scrapers.

2. The interior of the annular hearths is screened so as to allow easyinspection of the 7 whole hearth by opening one inspection hole rotatingwith a central platform, the said opening allowing any point of thehearth, as far as the periphery, to be reached for stirring and upkeeppurposes;

The material is divided and pushed in angular segments by new means. Forhelical hearths. these new means are characterized in that the operatingand position-determining nut member is not .vertically reciprocated fordividing the ore, as is the case in other helical-hearth furnaces.Moreover, the scrapers and their supports are balanced independently ofthe supporting platform, their operating mechanism and of the centralchamber turning helically at the same time.

In the accompanying drawing:

Figure 1 is a sectional diametral elevation of an improved furnaceaccording to the present invention;

Figure 2 is a sectional plan view, taken half way up, of the furnaceshowing the operating parts for the individual move- I ments of thestirring arms, which parts are disposed in the central rotating chamber.

Figure 3 is an elevation in part section and to a larger scale showingthe method of obtaining a particular obturation of the in- 00 terior ofthe hearths;

Figure 4 is a side elevation of one of the carriers for the arms andFigure 5 is a plan of the central portion partly in section.

The annular helical hearth 1 made of refractory material is surroundedby a sheetmetal housing 2, the whole structure being supported on ironpillars 3 and 4. J oists 5 are carried on the said structure and areprovided with pulleys 6 over which passes the cable attached to thescraper holders through the medium of the ball bearing 7,

a counter-weight 8 being attached to the other end of the said r0 e. Thefloor within 76 the central chamber is t e platform 9 carrying themechanism hereinafter described and the sectional-iron uprights 10 towhich ring members 11 are secured. The uprights 10 are braced at the topby cross-ties 67 supporting a centrally disposed guidin sleeve 12 inwhich the tube 13 is adapte to slide. The central cylindrical chamberthus formed is also guided at its base by the platform which bears onthe column 14 and" on the base column 15 provided with helical groove 16and firmly secured to the ground.

n operating nut member 17 is bolted to the platform 9, the threads ofthe said nut engaging the helical groove 16. Thee.;-.pitch of so thesethreads and ooves is e ual-to the distance between the earths 1.heinn'dersfde of the platform 9 is provided with te'eth 18 laid'on asurface inclined to the pitch of the helix. These teeth are in mesh witha as toothed wheel 19 rotated by the shaft 20 one end of which carriesthe pulleys 21 and 22 for rotation in both directions. The platform 9 isthus rotated by the toothed wheel 19 together with the nut member 17which causes the said platform to rise and sink while followinga helicaltrajectory having the pitch of the groove 16. a

In these circumstances all the movable parts together with the scraperholders 40 rise and s lk following ahelical movement at the same rate asthe nut member 17, the

itch of which is necessarily that of the reshaft to reverse at suitabletimes so that the direction of rotation of the platform 9 and themechanical lay-out carried thereon is reversed and moves helically theother 1 gther operations now to be described, take place uninterruptedlywhile the platform 9 is angularly reciprocated. A horizontal shaft 24 ismounted in bearings 25 on the platform 9 and carries a helically toothedwheel 26, an eccentric disc 27 actuating the connecting rod 28, and acrank disc 29 actuating a connecting rod 30. The shaft 24 is rotated bythe worm 31 driven by the shaft 32 suitably connected to an electricmotor 33 attached to the platform 9. The eccentric disc 27 and the crankdisc 29 are therefore rotated through the medium of the helicallytoothed wheel 26, the,

result being the two following movements.

The pin secured to one end of the connecting rod 28 engages a recess 48of. an

' oscillator 34 pivoted to. a fixed point 35 of a vertical support 36.The other end of the oscillator is attached to the pins 37 of a collar38 adapted to rotate around the member 39 connected to the scraperholders 40. The connecting rod 28 is raised and lowered by the eccentricdisc 27 so that'the oscillator causes the holders 40, and therefore thescra ers 41 working in the furnace proper, to use and drop continuouslyto the same extent. The lowerportion of the'member 39 has a circularextension integral with four stout ribs 42 engaging a collar 43 movedanularly as hereunder described.

he crank disc 29 actuates the connecting rod 30 throu h the medium of atrunnion 68, the other en of the said rod being connected to a crosshead30" moving in a guide 44. The cross-headcarries a pin 45 en aging asmall slide '46 guided in the end 0% the collar 43 which isthusrec'iprocated by means of the crank disc 29 and the connecting rod30. The

. amplitude of the movement of the said collar corresponds to theposition of the trunnion 68 on the crank disc 29. This collar moreoverangularly .moves the holders 40, and consequently the scrapers 41in thefurnace proper, through the mediumof the member 39 having four stoutribs engaging grooves cut in the said collar 43.-

The scrapers 41 working in the furnace proper are therefore verticallyreciprocatedstage the an ellipse, the material on the hearths beingdivided in sections having this shape. While the above-described twomovements are performed the platform rises owing to its rotation andfollows the hearths until the clutch or change-over mechanism reversesthe pulleys2l and 22 for lowering the platform to its starting point,whereafter it is raised again.

-While the platform 9 is sinking, the rise and drop of the holders 40and scrapers 41 is discontinued as follows: In the-operative pin at theend of theconnecting rod 28engages a recess 48 at the end of theoscillator 34 and is held in that recess by a link 49. A lever 50 ispivoted to a fixed point 51 and'is operativel connected to a non-fixedlever 53 through 'nks 52. The last-mentioned lever takes bearing on ashaft 54 carrying a movable weighted lever 55 the lower end of which isprovided with driving dogs adapted to co-operate with other'dogs Avertical shaft 56 rotates a toothed wheel 57 meshing with a bevel wheel.58 keyed to the shaft 54 to .which theweighted lever 55 is likewisesecured. Theother end of the shaft 56 carries an arm 59 the end offwhichis adapted to come in contact witha suitably disposed abutment 60. Whenbearing on the said abutment, the arm 59 moves angularly and actuatesthe gear-wheels 57, .58 and the weighted lever 55 which thenvtilts overand actuates by means'of-its dogs the non-fixed lever 53 which in turn 0crates the connecting rod 28 through the inkwork. The end of the saidconnecting rod is thus moved into a cut-out portion 61 of the oscillator34 and the pin on the connecting rod 28 leaves the recess 48'to moveidly in the said cut-out portion 61. From that time the oscillatorremains motionless until the lever 59 is again operated by an abutmentand by reversing the mechanism moves again the end of the connecting rod28 to the recess 48 of the oscillator 34 which is-now again operated bythe said connecting rod. Thus by virtue of the above arrangement thevertical reciprocation of the oscillator 34 actuatin the holders 40 andthe scrapers 41 is discontmued at the desired time.

1 The weight of the moving elements is divided in two, each weightportion comprising a separately balanced set of elements. The first suchset comprises the platform carrying the lower actuating mechanisms andthe metal framework supporting cast iron ring members for. closingofl'the hearths. The second set comprises the holders'40, the scrapers 41,

the rotating collar 38, the member 39 (which I transmits the movement ofthe connecting rod 28 to the holders 40 and the scrapers 41),

the connecting rod 30 andthe collar 43. F

set is separatelybalanced by a cable passing I pass over pulleys 65 andon which counter weights 66 are hanging. As a consequence,

' the threads of the nut member 17 are relieved from an stress, the saidmember only guiding the p atform 9 vertically. In fur-.

naces hitherto known the nut member car-' ried the rotatin collar of thetilter on the outside and per ormed the duty of transmitting to thecentral shaft the vertical reciprocatlon imparted by the tilter. Thisinvolved a marked wear on the inner threads of the nut member, leadin toirregular working due to the stresses being transmitted through theedges of the steeply inclined threads. In

the new arrangement the nut member is not Vertically reciprocated andhas as its sole object to guide a perfectly balanced set'of 7 elements.The scrapers 41 and their holders 40 are separately balanced, the.balancing being as accurate as possible so that the only duty-to beperformed by the machinery is that of the scrapers 41 dealing with thema terial.

Suitably shaped ring members 11 are carried on sectional iron uprights10 supported on the platform 9. .These rings face'the refractory hearths1 and are protected from the I heat of the furnace. Theyare also cooledto an extent by the air circulatingin the central chamber of thefurnace. These ring members 11 are shaped so that they may be tted withv sheet-iron or cast-iron screens 69 inwardly lined with asbestos sheets70 and 71 insulating the heat of the furnace proper. These v F i suppying fluid. to the scrapers 41.

screens are entirely gas-tight, as their upper and lower edges lie insand joints. In addition, they may also be covered externally withcoarseheat-insulating material 72. One or more of these screens'may be made toafford passage to air into the furnace through vents 3 or suitablyplaced apertures.

A whole hearth of the furnace is rendered visible by removing one of thescreens or opening one The air-blast may for example beled in throughthe base of the helically-gr'ooved' column 15, pass along the column 14and issue gases.

through ports 7 5' to reach the interior of the holders 40 from which itreaches the scrapers 41 through the pipe 76. The scraper 41 within thefurnace proper is bolted-to a slide 77 moving on guides 78 which areloosened when a scraper is to be placed in position or dismantled. Inthe latter case the slide 7 7 tightened to the guide 78 is slightlyslackened and the scraper 41'may be bodily removed from the furnacebefore undoing the bolts whereby it is secured to the slide 77.

Thus an unserviceable scraper may be re placed in a few minutes by a newone, the sliding closure 7 9' carried on the scraper 41 leaving a largefree space, whenremoved, for taking a scraper out, whatever itscondition when dismantled. The essential feature of rapidly removing asore er is inherent to the general arrangement 0 the furnace and ispossible owing to the method of closing off the hearths of the furnace.

The scraper41 being hollow and projecting out of the furnace proper, theheat of the said scraper mav be naturally exchanged through the end 80with that of the outer surrounding air without the need of anyartificially sup lied cooling fluid. This feature is not to e found inany other furnace. Cooling may of course be intensified by circulatingair or water' or any other fluid throu h the scraper holder, ashereinbefore described. 1

The lower end of the furnace is provided with a water, sand, or oil seal81 efiiciently preventing any air from entering the furnace save throughthe right channels, a seal 82 of similar nature being rovided at the uper portion to prevent t e escape of sulpl iur I claim:

'1. A furnace for roasting sulphurous and other ores comprising incombination a helical hearth, a central vertically movable chamber, acrown wheel having the form of a toothed helical incline for verticallymovingsaid chamber, and means for operating crown wheel.

. 2. A furnace for roasting sulphurous and other ores, comprising incombination a helical hearth, a central vertically movable chamber,scrapers actuated by said chamber, means disposed within the centralchamber for forming the material under treatment into angular sections,and means disposed within the central chamber for advancing saidmaterial, such means being actuated in the movement of said chamber.

3. A furnace for roasting sulphurous and other ores comprising 'incombination a helical hearth, a central vertically movable cylindricalchamber, a central stationary column, scraper holders mounted thereon,

means for imparting to said scraper holders a helical movement, saidscraper holders in their helical movement turning and cutting in thematerial and means for imparting to said scrapers an'inde endentvertical movement.

'4. A furnace Ear roasting sulphurous and other ores comprising, incombination, a helical hearth, a central vertically movable chamber, acolunin havingha helical groove, a nut member supporting t tral chamber,a pinion for rotating said chamber, and agitating and cutting mechanismassociated with the grooved column and said chamber, therebytransforming into a helicoidal movement the rotary movement effected bythe driving pinion.

5. A furnace for roasting sulphurous and other ores comprising, incombination a helical hearth, a central vertically movable chamber,means for cutting the material under treatment, a balanced lever fortransmitting motion to said cutting means, a column, an axial collarupon said column, trunnions upon said balanced lever, agitating armsactuated by said balanced lever, and means for producing an alternativevertical reciprocation of said agitating arms.

6. A furnace for roasting sulphurous and other ores, comprising incombination, a helical hearth, a central vertically movable chamber,rings upon said chamber, a frame supporting said rings, a drivingplatform supporting said frame, circular plates carried by sa1d frame,said circular plates being covered with insulatingv sheets, orifices insaid circular plates and valves closing said orifices.

' 7. A furnace for roasting sulphurous and other ores comprising, incombination, a helical hearth, a central vertically movable chamber, acentral column, arm holders having hubs carried by said colunm,agitating arms carried. by said arm holders and displaced laterally fromthe hub of said arm olders, a lateral slide, means -fixin said armholders to said lateral slide, sai arms extending from said centralchamber: into said hearth.- 1

. 8. A furnace for roasting sulphurous and I otherores comprising, incombination a helical hearth, a central vertically, movable chamber,counter weights balancing said central chamber in the movement thereof,a central column, arm holders carried by said central column, agitatinarms mounted upon said arm carriers wit in said central chamber, acounter weight balancing said agitating arms and arm carriers in theiralternative vertical reciprocating movements and means for operatingsaid arms.

I In testimony whereof I have signed my 7 name to this specification.

to 1 V EMILE BRAc e walls of the cen

